combine_nearby_stops: Combine nearby stops

In gtfstools: General Transit Feed Specification (GTFS) Editing and Analysing Tools

Combine nearby stops

Description

Merges the stops that are within a given distance of each other into a single stop, and updates the tables that refer to them. Useful to build routing networks or to analyse the feed by station rather than by platform.

Usage

combine_nearby_stops(gtfs, max_dist)

Arguments

gtfs	A GTFS object, as created by read_gtfs().
max_dist	A number. The maximum distance, in meters, between two stops merged together.

Value

The GTFS object with the merged stops.

Details

Stops with a parent_station are first merged into one stop with the stop_id of the station, regardless of the distance between them, named after the station if it's listed in stops or else after its platforms. Stops are then merged by distance, closest pairs first, so that every pair of stops merged together is at most max_dist apart (great-circle distance, as in get_stop_distances()). Stops already merged by their parent station are compared by the mean of their coordinates, so their own platforms may be farther apart. Stops without coordinates are only merged by their parent station.

A merged stop has a stop_id and a stop_name made of the ids and names of the merged stops joined by "-" (repeated names listed once) and the mean of their coordinates; its other fields (e.g. zone_id, level_id) are those of the merged stop whose stop_id comes first. Only the first entry of a stop_id listed more than once in stops is used. Merged stop_ids are ambiguous when the original stop_ids include "-", and an error is raised if two resulting stop_ids are identical.

The result has only plain stops (location_type 0) without parent_station: stations are replaced by the stop merged from their platforms, and stations without platforms, entrances, generic nodes, boarding areas and pathways are removed. The stop_ids of merged stops and stations are updated in stop_times, transfers, stop_areas, location_group_stops and fare_leg_join_rules; references to removed stops are left as they are (they and their translations can be removed with remove_unused_ids()). Transfers between stops merged together become transfers within the merged stop, and when several transfers end up with the same stops, routes and trips, only the first is kept, even if their transfer_type or min_transfer_time differ; the other fields of transfers are not changed. Duplicated rows of stop_areas and location_group_stops are removed. Translations of merged stops are not updated.

An error is raised if max_dist would merge all stops into a single one. Large values of max_dist in dense feeds raise a warning when comparing the pairs of stops may use a lot of memory, or an error when there are too many pairs. Feeds that cross the antimeridian are not supported.

See Also

get_stop_distances(), merge_gtfs()

Examples

data_path <- system.file("extdata/spo_gtfs.zip", package = "gtfstools")
gtfs <- read_gtfs(data_path)
nrow(gtfs$stops)

combined_gtfs <- combine_nearby_stops(gtfs, max_dist = 100)
nrow(combined_gtfs$stops)

gtfstools documentation built on Oct. 28, 2026, 5:13 p.m.